Receptors and signaling (complete)

Question 1

What are the three parts of the cell signaling cascade

Answer 1

1. Reception
2. Transduction
3. Response

Question 2

What is a transcription factor

Answer 2

a protein that interacts with DNA and increases/decreases transcription of specific genes

Question 3

How specific are transcription factors

Answer 3

they are very specific, each transcription factor only influences the transcription of certain genes

Question 4

what do protooncogenes do?

Answer 4

they act as positive regulators of cell growth. they induce tumors when they are overactive

Question 5

What do tumor suppressors do

Answer 5

they act as negative regulators of cell growth. when they lose function tumor growth results

Question 6

What are the four secondary messengers

Answer 6

1. cAMP
2. IP3
3. DAG
4. Calcium

Question 7

What enzyme activates cAMP

Answer 7

adenylate cyclase

Question 8

What enzyme activates IP3

Answer 8

phospholipase 3

Question 9

What enzyme activates DAG

Answer 9

phospholipase 3

Question 10

What is the process by which Ca++ is activated

Answer 10

IP3 is activated by phospholipase 3, then the IP3 goes on to activate Ca++

Question 11

What is the structure of G protein-coupled receptors

Answer 11

a protein made of 3 subunits bound to a receptor

Question 12

what are the three subunits of the G protein that is bound to the receptor

Answer 12

alpha
beta
gamma

Question 13

Which protein subunit attaches the GDP

Answer 13

the alpha subunit

Question 14

What happens first when the G protein coupled receptor binds a ligand

Answer 14

the GDP on the alpha subunit gets phosphorylated into GTP

Question 15

What happens after the GDP on the alpha subunit of the G protein coupled receptor is phosphorylated into GTP

Answer 15

the alpha subunit dissociates from the beta and gamma subunits

Question 16

What happens after the alpha subunit of the G protein-coupled receptor dissociates from the beta and gamma subunit

Answer 16

the activated alpha subunit goes and activates an enzyme

Question 17

What are the steps involved in the G protein-coupled receptors messaging process

Answer 17

1. receptor portion binds a ligand
2. alpha subunit (while associated with the beta and gamma subunit) has its GDP phosphorylated into GTP
3. the alpha subunit dissociates from the beta and gamma subunit
4. the activated alpha subunit goes and activates an enzyme. (adenylate cyclase or phospholipase 3)
   A. if it activates adenylate cyclase then it will produce cAMP (secondary messenger)
   B. if it activates phospholipase 3 then it will produce DAG and IP3 (secondary messengers)
   C. IP3 may then go on to activate Ca++ (secondary messenger)

Question 18

is Receptor Tyrosine Kinase an enzyme or a receptor

Answer 18

BOTH

Question 19

what happens when one receptor tyrosine kinase binds a ligand

Answer 19

nothing. It has to wait until the adjacent receptor tyrosine kinase binds a ligand as well

Question 20

What happens when two adjacent receptor tyrosine kinases each bind a ligand

Answer 20

then the receptor tyrosine kinases will dimerize (come together) and then they are activated

Question 21

What is on the intracellular portion of the receptor tyrosine kinase

Answer 21

3 tyrosine spots which can easily be phosphorylated

Question 22

What is a first messenger

Answer 22

a ligand or hormone that begins cellular messenging

Question 23

How many ATPs are needed to completely phosphorylate a receptor tyrosine kinase dimer

Answer 23

6 ATPs are needed

Question 24

What are the steps involved in the receptor tyrosine kinase cellular messaging process

Answer 24

1. BOTH receptor tyrosine kinases bind a ligand
2. the receptor tyrosine kinases dimerize (come together)
3. 6 ATPs phosphorylate the tyrosine locations
4. The activated receptor tyrosine kinases initate a cellular response

Question 25

What are cytokine receptors

Answer 25

receptors that bind cytokines and transduce signals

Question 26

What are intracellular/nuclear receptors

Answer 26

receptors that aren’t found in the plasma membrane but in the nucleus or within the cell